Starter for explosive-engines.



R. O. HULL.

STARTER FOR EXPLOSIVE ENGINES.

APPLICATION FILED AUG.26,1912.

Patented J an. 14, 1913 1,050,739. 4 SHEETS-SHEET 1.

FILE I I 44 Z3 21 b o A M 7 4 k 4? 5 4a 1 20 H 50 i! 9 o O W V g b L rLight 33 2 we -n I I :1 1 i 1 0 13 16 :H

32. L f J zlflVENTOR 2 I I av R. C. HULL.

STARTER FOR EXPLOSIVE ENGINES.

APPLICATION FILED AUGDZG; 1912.

Patented Jan. 14, 1913.

4 SHEETS-SHEET 2.

INVENTOR f; ATTORNEY BY W16 7 V WW4 R. C. HULL.

STARTER POE EXPLOSIVE ENGINES.

APPLICATION FILED AUG,26, 1912.

1,050,739. Patented Jan. 14,1913.

4 SHEETSSHEET 3.

4 A TTORNE Y t v M INVENTOR M 5 R. G. HULL.

STARTER FOR EXPLOSIVB mamas.

I APPLICATION FILED AUG.26, 1912. 1,050,739, Patented Jan. 14, 1913.

4 SHEETS-SHEET 4.

FIG. 7-

II 43 59 47 13 4 31 29 W x J? 28 97 w n I k FIG. 8-

W W 2am BY I L UNITED sTAr s IZATENT OFFICE.

STARTER FOB EXPLOSIVE-ENGINES.

Specification of Letters Patent.

Patented Jan. 14, 1913.

Application. filed August 26, 1912. Serial No. 716,992.

T 0 all whom it may concern I Be it known that I, ROBERT C. HULL, acitizen of the United States, residin in the cit of Philadelphia, countyof P iladelphia, and State of Pennsylvania, have invented a new anduseful Starter for Explosive-Engines, of which the following is aspecification.

My invention relates to a starter for explosive engines, such as gasengines, gasolene engines, and the like, which are not self starting butrequire to be cranked, or turned over to cause a sucking into thecylinder or cylinders of an explosive mixture and the compressionthereof; this mixture when ignited by the. usual ignition means forcingthe piston or pistons forward to deliver to the crank shaft the initialimpulses as a result of which the engine itself draws or sucks in andcompresses the explosive mixture automatically causing automaticcontinued operation of the engine.

My invention relates particularly to electromagnetic or electro-dynamicmeans for starting an explosive engine, the electro magnetic orelectro-dynamic means converting electrical energy into mechanicalenergy for cranking or turning over the explosive engine for thepurposes above doscribed;

As early as the year 1886, I believe, it was proposed to impart theinitial movement to the piston or pistons of an explosive engine by anelectric motor, comprising relatively rotating armature and fieldmagnet, the rotatable member of the motor, as the armature, beingdirectly secured upon the engine crank shaft or suitably geared theretofor engine starting purposes. And even at the present time, particularlywith regard to the explosive engines employed on automobiles or likemotor vehicles, such an electric motor is resorted to for enginestarting purposes, a suitable source of electric energy being providedto drive the motor. Such an electric motor is well understood tocomprise an armature having the usual commutator with brushes bearingthereon, the resultant relative movement. between brushes and commutatorcausing the progressive shifting. of the ma etic poles of the armature,produced by t e current in its winding, such progression of the magneticpoles tak- Hi arina iure itself; And it is further characace withrespect to the body of the tcristic ofi such an electric motor that therelative movement between the brushes and commutator correspondsprecisely with the relative movement between armature and field magnet,because the commutator is in fixed relation with the armature and thebrushes in fixed relation with respect to the field magnet. From such anelectric motor and all other forms of starters my inventionsharply'contrasted, in that I employ tlurotor of my electro dynamicmeans a member which exhibits magnetic poles which remain substantiallyfixed with re spect to the body of the rotor, and such same; and asstator I employ a. magnetic system in which the magnetic poles progresswith respect to the body of the stator. And my invention is furthercontrasted in that the switching or commutating means for ,poles in thestator may be detached or dislmembcred' from the electro-dynamicdeviceand removed to any suitable point, as upon the dashboard of anautomobile, where, in operation, such commutating or switching means maybe operated solely at the will oi the driver and are not necessarilydriven as in an ordinary electric motor in perfectly definite relationwith respect to the moving element of the motor.

In one of its aspects my invention may be viewed as employing anelectric motor dismembered to the extent that the moving part of thecommutator mechanism does not necessarily or at all times rotate infixed relation with and is not drivenby the rotating element of themotor but may be located at a distance from the motor at a point wherethe control is to be exercised and there moved at the will of theoperator to cause relative movement between the rotating and stationaryelements of the motor, without as in the case of an ordinary mo- 'tormovement of the movable part of the commutator mechanism by the rotatingelement of the electro-dynamic means.

In another of itsv aspects my invention may be viewed as employing anelectric motor. dismembered to the extent that the moving part of thecommutator mechanism, whil'ejt may rotate in fixed relation and bedriven by the rotating element of the motor, is not necwsarily alwaysmechanically and electrically in connection with the fixed part magneticpoles therefore rotate with the causing the progression of the magneticof the commutator mechanism, for, by my invention, these two parts maybe mechanically and electrically connected at the will of the operator.

A further feature of my invention resides in the fact that the windingof the rotor is traversed by a relatively heavy or large currentadmitted to such winding through collectors and slip rings whose onlyfunction is to maintain electrical communication and not to commutate,with the result that troubles attendant upon the use of a com mutatorand brushes for heavy currents forming a part of the armature of anordinary electric motor are not encountered; with a relatively smallcurrent in the stator, this being the current which is controlled andcommutated.

As is well understood with respect to an explosive engine, the negativetorque offered by the same during the cranking or "turning over forstarting purposes, is not uniform, but passes through a more or lesssharply defined maximum and falls away again to lesser values. By myinvention,

though I do not limit myself thereto. I may,

employ electro-dynamic means which will produce a non-uniform torquehaving well defined maximum points. And these points of max num positivetorque shall preferably occur substantially simultaneously with themaximum negative torque exerted in op position by the engine. The numberof points of maximum positive torque developed by the electro-dynamicmeans may be greater than the number of points of maximum negativetorque exerted in opposition by the engine, but the former points mayalways be a multiple of the latter points so that in all cases one ofthe former points shall occur substantially simultaneously with one ofthe latter points. And i prefer that the'positive torque developed bythe electrddynamic means shall always be at least as great as thenegative torque of the engine exerted simultaneously therewith.

My invention resides in the apparatus for starting an explosive engineherein described.

My invention resides in the features here ina'lter described andclaimed.

For an illustration of some of the forms my invention may take, butWithout limiting my invention thereto, reference is to be had to theaccompanying drawings, in which:

Figure 1 is a longitudinal cross-sectional view. some parts inelevation, through a part of an automobile or similar motor vehicle.Fig. 2 is a diagrammatic view illustrating the circuits of and means forcontrol of one form of electro-dynamic starter. Fig. 3 is a diagrammaticview of a modified form of'startcr and its control circuits. Fig. 4 is adiagrammatic view ofa further modification of the electro-dynamicstarter and its control circuits. Fig. 5 is a graphic representation ofthe torque curve of a single cylinder of an explosive engine, as

, a four cylinder engine, and a torque curve of an electro-dynamicstarter therefor. Fig. 6 is a graphicrepresentation of similar torquecurves of a six cylinder engine and of a starter therefor. Fig. 7 is adiagrammatic view of a modified form of starter system. Fig. 8 is afragmentary view illustrating structure of the commutating mechanism ofFig. 7.

Referring to Fig. 1, the frame or chassis 1 of an automobile or likevehicle has secured thereto the explosive engine E here illustrated, byway of example merely, as having four cylinders 2, 3, 4, and 5, theengine E being inclosed in the hood 6 extending from the dash board 7 tothe radiator 8. -Upon the shaft 9 of the engine is secured the fly-Wheel10, which, however, may be omitted if desired. Secured upon the shaft 9is the rotor element 11 of the elcctro-dynamic starter, the same beingsurrounded by the stator member 12 provided with lugs 13 resting uponand secured to the frame 1. Or these lugs 13 may rest upon and besecured to or integral with the engine bed, so that the engine andelectrodynamic starter may he removed as a unit. Between the engineshaft 9 and the driving shaft 14, leading to the running gear, notshown, may intervene the clutch comprising the driving member 15 and thedriven member 16 operated by any suitable means as the lever l7 nearthe, seal l8 of the driver. near which are disposed also the usualsteering Wheel 19 and other (unil'fil members 20 and 21. Upon the dashboard 7. or at any other suitable point within reach of the driver. aredisposed the switch 2'2 and the switching or eommutaling apparatus 2inclosed within the casing 24 and disposed upon the base 23, the crank26 disposed out side of the casing 2t for operation by the driver ashereina 'lcr described. At any suit able placeon the automobile or.tl1l(l0 is mounted any suitable source of cos-sa nt such as a storagebattery 97. Referring" now to Fig. 2 one arrangement of my electro-dvnumic starter and its control are illustrated Here the rotor ll, securedupon the engine shaft 9, as by a spider r other suitable means, notshown, compris s a core ll of iron or other suitable magnetizablcmaterial upon which is disposed a winding or conductor 28 with whichconnection is made through conductor 29 permanently connected to theslip ring 30 upon which bears a brush ill in electrical conununicationthrough con doctor 32 with one terminal of the iron 27. At adiametrically opposed point the winding 28 permanent connection madthrough conductor 33 with the slip ring 34 upon which bears the brush 35which con- Ill) insulated from each other and rotate with the rotor 11.V v

The stetor 12 comprises the rin or yoke 38 of iron or other suitableiiig'i'ietic n12:- terial carrying the our poles 39; 4'0, 41, and 42each provided with s magnetizing coil. 43. These coils 43 arc, hereShow]; as connected in series with each other and all wound in the somedirection with respect to the poles upon which they are From a pointbetween one pair of coilsa conductor extends to a segment 45 0% thecommutator or switching afipsrut-us 23. From a point between anotherpairof coils theconductor 46 extends to s segment 47;- frorn a pointbetween another pair of coils extends the conducizor 48 to mothersegment c9; and similerly from a point between the remaining pair ofcoils extends a con doctor-'50 lo the segmentkil.

fihe ink or lever 2o is secfir'ed to" the shaft 52- ceriried by androtatshle' with re spect to the base carryi-rr l the segments 45, 47,llland 51. Insulated each ther and rotatable with the shaft 52 and lever26 are the sli rings 53 and 54' upon which bear the brus cs 55 and 56respectivel the brush 55 being' connected through c u'ctor 57 with oneterminal of the source" 27 and the brush 56' connected through conductor58'with switch contact 37.- Movable with the shaft 52 and handle 26 arethe brushes 59 and 60, insulated fr'orneach other, and electricallyconnected respectively with the slip rings 53 and 54.

n closure of the switch 22 upoiioomtact 37 current will flow from thelower, for example, positive terminal of the source 27 through conductor32, brush 31, slip ring 30, conductor 29, through both halves of thewinding 28, returning through conductor 33, slip ring 3 l, brush 35,conductor 36, throng: switch 22 to the negative terminal of t source 27.The flow of the current through the winding 28 magnetizes the core 11 ofthe rotor to exhibit north and south poles on opposite ends of adiameter, which poles remain in substantially the same position withrespect'to the core 11 during its to" tation.

Due to'the closure of the switch 22 current also flows from the lowerterminal of the source 27 through conductor 57, brush 55, through slipriiig 53, brush 59, segme'iit l7, conductor 46, to the point a Where itdivides flowing through the right hand find lower coils 43 in series tothe p int b. andflowing also through the upper and loft hand coils 43 tothe point 6 thence Eli rough co n' ductor 50 to segment 51, through 60,slip ring 54:, brl1sh 56', conductor 58; through the switch 22 to therationin terminal of the so'flrce 27. In conso' lie'nce the? fides ofthe'poies and 41 will glib-loll sou-fh poles, for exanrole, while thefldes of the-{0112s 39 and 42 will exhibit north poles.

such case at with the horizontal from a.

point midway between the poles 39 and 42 through apoint midway betweenthe poles and 41 as indicatedby the arrows 61.

The direction of the axis of the field of the rotor 11 extends in thedirection of the arrows 62. There will then be n react-ion be tweenrotor and stator producing motion of the rotor 11 in a clockwisedirection as viewed in Fig. 2 tending to bring these msgnetic axes ofthe stator and rotor into coinciclenc'e. This reaction produces a torqueon the shaft 9' rotating the same in clockwise direction when-viewedfrom the right hand end Fig. 1. The movement of the rotor 11- ho'we'xferwill not continue, as in an ordinary electric motor having itscommutator and brushespdircctly attached to it and causing relativeshifting of the field of th?! armature with respect to itself inopposite direction to jthc rotation of the arn'rature and to exactly thesome extent of the rotation, whereby the armature continues to revolve.The rotor'll will come to rest unless the handle 26 is med to carry thebrushes 59 and into cont-act with segments 49 and 45, and in doirig' socurrent will flow from the source 27 through conductor 57, brush55, slipring 53, brusli 59, segment 49', conductor 48 to the point of where itdivides, part goin in. series through coils 43 onpoles 39 an '40 itq thepoint 0 and part passing in series fthrough the coils 43 on poles 42 and43 to Ethe point (1. Now the faces of poles 42 and while poles 39 and40' 41 exhibit south poles exhibit north poles. in other words the axisof the magnetic ficldpf the stator h ts he axis of the magnetic field ofthe stator extends in shifted in a clockwise direction through 96".

But the axis of the magnetic field of the rotor has remainedsubstantially constant with ties t to the rotor body and in consequeries t e rotor is rotated through a further And so on for thesuccessivepositions of the handle 26fmoved in clockwise direc lion, Fig.2, the rotor revolves 90 for each i the shaft 9 of the engine whichWillsfurt; its opposing torque having been overcome by'the rotor 11,- itbeing assumed of course that the ignition \apparatus, not shown, hasbeen set into operation and 't hethrott l'e', not shown, has beenopened. After the engine is started the switch 22 maybe opened until 4successive position of the handle 26, cumin-g torque is a maximum, andfour alternate positions at which itis a minimum. The rotor is so placedas to its angular position upon a the shaft 9 with respect to the enginecranks that for every maximum occuring in the negative torque of theengine there will simultaneously occur a maximum in the torque of therotor, the torque exerted by the rotor 11 upon the shaft 9 at such timebeingin excess of the negative torque exert-ed upon the shaft 9 on theengine at the same time.

remain seated inthe machine and move the crank 26 in proper directionand the rotor 11 will execute movements following the movements of thecrank 26, to crank the engine. And it is further'apparent that inthisarrangement my clcctro-dynamic starter does n t operate like theordinary electric motor which continues to rotate so long as it remainsin communication with a source of energy. Notwithstanding the closure ofthe switch 22 the rotor 11 will not continue to rotate, because thebrushes 59 and 60 are mechanically independent ofthe rotor and are notshifted synchronously with it, as is the case of an ordinary electricmotor where the brushes and commutator are mechanically shift-ed withrespect to each other in syfichronism with the movement of the mm ablemotor element. 4

' In Fig. 3 I have-shown the stator ring 38 carrying cightpoles 63, 64,65, 66, 67, 68.

'69, and 70 having thereon coils 63' to '70 respectively. The commonterminals of coils (33 and 64' are connected by conductor 7 1 with thecommon terminals of the coils 67' l|l(l (38 and with segment 49 of thecom:-

mutating apparatus. Similarly the common terminals of the coils 63' and70' are connccted ,by conductor 7 2.with the common terminals of thecoils 67 and 6G and with the segment 51. Similarly the common ter minalsof the windings 70' and 69 are connected by conductor 73 with the commontramiuals of coils G6 and and with the segment. 47 .-\nd similarly thecommon terminals of the coils iti'hnd 69 are connected ihrough conductor74 with the common ter miuals of coils fl t and 65 and the segment ii.The rotor ii in this case has in place of the two windings shown in Fig.2, four windings 2 each extending through a quadrant only diametricallyopposite points or the winding being connected to one slip ring 30 whilediauu-trically opposite points,

at right angles to the first named points, are connected to the sliprings 34 and. through the respective brushes 3-5 and 31 with the source27, when the switch is closed. In consequence the rotor exhibits -twonorth the axis of the other poles and two south poles, the axis of onepair of these poles being at right angles to alr.

lVhenfthe switch 22 is closed and the handle lever 26 rotated, the rotorwill fol.- low in its movements the movements of the lever 26, itsmagnetic poles remaining substantiallyfixed with respect to the. rotor.The stator, however, due to the connections of the windings asdescribed, exhibits two neighboring north poles, with two neighboringnorth poles diametrically opposite; also two neighboring south -poleswith two neighboring south poles diametrically opposite. As the handle26 is rotated through 90 the magnetic axes of the stator are rotatedthrough only 45, with the result that the handle 26 must make twocomplete revolutions for one complete revolution of the rotor 11. Hereagain the arrangement is such that the torque of the rotor 11 hasperiodically recurring maxima and minima and, as previously stated, amaximum torque exerted by the rotor 11 shall occur substantiallysimultaneously with the maximum negative torque by the shaft 9 exertedthereon by the engine. And as in the previous case the rotation of thehandle 26 causes a rotationof the shaft 9 for engine starting purposes.

In Fig. 4 the stator ring 38 carries six poles 75, 76, 77, 78, 79, andcarrying respectively the magnetizing coils'75 to 80.

In this case the.s\vitching mechanism has six segments 81.. 82, 83,84,and 86. The segment 81 is connected through conductor 87 with the commonterminal of the coils 75" and 80; segment 82 is connected throughconductor 88 with the common terminals of coils 79 and 80'; segment- 83is connected through conductor 89 with the common terminal of coils. 7S'and 7?); segment- 84 is connected through conductor 90with the commonterminal of coils 77 and 78; seg

'ment Siiis connected through conductor 91 with the common terminals ofcoils 7G and 77'; .and segment 86 is connected through conductor 92'withthe common terminals of coils 75 and 76. The rotor is similar in itswinding to that shown in Fig. 2. Here a sixth of a revolution of thehandle 26 causes a shifting of the magnetic axis of the stator through asixth of a revolution, that is, through 60 with respect to the stator.In the arrangement of Fig. 4 three neighboring poles simultaneouslyexhibit like polarity while the three opposing poles In Fig. 5 ordinatesrepresent torque values and a-bscissse represent time or an-' gularpositions of the engine crank shaft. The lower curve P represents, ingeneral, the thrust against an engine crank, or-represents generally thetorque of one cylinder of a four cylinder engine. The torque increasesfrom the point It to a maximum at the point A: and diminishes again tothe point Z. The upper curve Q represents the torque curve of a rotor ofan electro-dynamic starter involving one form of my invention. Here itwill be noted that a maximum occurs at the point m coincidingsubstantiallyv in time with the maximum is of the engine torque. And thepoints it of minimum torque represent torques substantially equal to orlarger than the maximum torque is.

Th Fig. 0 the lower curve T represents the combined crank thrusts of twocylinders of a six cylinder engine during compression period and theupper curve Q is the torque curve of my electro-dynamic starter whenhaving six poles, and commutator of six segments, and rotor, all asillustrated in the example of Fig. 4. Here again a maximum 122/ occurssubstantially simultaneously with the maximum la. It is to be understoodhowever that my invention is not limited to starters exhibiting withrespect to the engine the relations exemplified in Figs. 5 and .6 forthe relative values of the torques; and the two curves in each figuremay be other than indicated. But as stated it is preferred that amaximum torque be exerted by the starter substantially simultaneouslywith the occurrence of the maximum opposing torque on the part. of theengine shaft.

In Fig. 7 is shown a form of starter whereby the operator need not turnthe brush crank 26, of Fig. 2 for example, but in which one element ofthe commutator moves in synchronism or definite relation with therotor,the other element of the commutator being stationary as regardsrotation, and capable of connection and disconnection electrically andmechanically from the rotating element of the commutator at the will ofthe operator.

I11 Fi 7 the frame, rotor, stator, windings an connections are similarto those indicated in Fig. The shaft52 revolves in bearing 94 set in thedash board 7, or any other suitable location, and in bearing 99 in asuitable sup ort 100, said support 100 being bolted to 'ash board 7 bbolts 105. At one end of shaft 52 is a pulley 95 upon which travels abelt or chain 96 to pulley 97 secured upon shaft 9. Thus when shaft 9revolves shaft 52 revolves in synchronism or in definite relation withit. Attached to the shaft 52 is arm 110 carrying brushes 55, 56,

5t) and 60; brushes 55 and 59 being connertetl together by conductor 102and brushes 5t; and 60 being connected together by conductor 101. Base25 is movable longitudinally of the shaft 52 but prevented from rotationby the bolts 105 and rods 106, the latter mechanically connected to thecross piece 108 carrying the handle 107. Segments 45, 47, 49 and 51 andslip rings 53 and 54 are secured to ,the insulating piece 25, and areheld away from the brushes 55, 50, 59'and 60 by the springs 109. Slipring 54 is connected to one terminal of the source 27 by conductor 57,and slip ring 53 is connected through conductor 58 to the contact 37 ofswitch 22. \Vhen the handle 107 is pushed inwardly in opposition tosprings 109, brushes and 56 are engaged by slip rings 53 and 54respectively. Brushes 59 and 60 are connected to the commutator segments45, 47, 49 and 51 depending upon the position of the armature 110. Asshown rush 59 is in electrical connection with segment 51 and brush 60is in electrical connection with brush 47. Now if switch 22 is closed,the current will flow through the rotor as described in connection withFig. 2. As to the stator windings, the current will flow from the source27 through conductor 57 to slip ring 54, to brush 56, to brush 60, tosegment 47, through conductor 46, to the point a and thence to thestator windings to the point I), as previously described in connectionwith Fig. 2, then by conductor 50 to segment 51, to brush 59, to brush55, to slip ring 53, through conductor 58 to the other terminal of thesource 27. The reactions between rotor and stator will cause the rotorto revolve-in clock-wise direction and so revolvingwill drive the shaft9 which will revolve shaft 52 and the brush holder will shift so thatthe brush 60 will connect with the egment 49 and brush 59 will connectwith segment 45. The field,

in the stator is correspondingly shifted and the reactions between rotorand stator will continue until the engine is started, when the handle107 may be released and brushes and commutator segments mechanically andelectrically disconnected by springs 109. As the engine continues to runthe brushes may be rotated, but, being out of contact with thecommutator segments, the Wear of brushes and commutator segments isavoided, as these are in mechanical and electrical connection only whilethe engine is being started.

The commutator of the rotating armature and the brushes of an ordinarymotor for self starting are always in mechanical and electricalconnection. The commutator brushes of the stator of my starter may -beput in mechanical and electrical connection and separated at will, thussaving wear when not in use. This principle applies Whether one of theelements of the commutator revolves synchronously with the shaft of thestarter or not. If however both comniutator and brushes are stationarywhen not in use when starting there will be no wear, and it is notnecessary to separate them mechanically and electrically.

It is to be understood that my invention is not limited to a statorwhich is provided with the concentrated poles or windings as shown, butthatv a stator having a great number of sections of windings may be employed, similar to a direct current armature winding, in which case. thenumber of seg ments in the switching apparatus or commutator apparatuswill be correspondingly increased with the result that the maxima andminima of the resulting torque curves will not be so contrasted as inthe case of the apparatus illustrated, but will have a characteristictorque curve which is more nearly a straight line, that is, indicating amore nearly uniform torque Nor do I wish to be limited to apparatus forstarting an explosive engine of any particular type or number ofcylinders, for my invention is broadly applicable to all types ofexplosive engines, and in fact to any other devices which, for starting,must be turned over or cranked.

I prefer that the windings upon the rotor of my starter shall berelatively coarse and be traversed by relatively heavy current,

hile the windings on the stator shall be aversed by relatively smallcurrent. In such case, since continuous slip rings continuously inconnection, with brushes are employed, there will be no s arking atthese members notwithstanding t e rotor is traversed by heavy current.

It is to be further understood that I may use separate sources ofenergy, one for enerizing the stator and another for energizmg therotor. Or the stator may be subjected to either the entire or less thanthe entire electric pressure of the source and the stator may besubjected to either less than the entire or the entire pressure of thesource.

\Vhile I have illustrated the rotor directly connected upon the engineshaft 9, it is to be understood that it may be connected to the engineshaft. through any suitable gearing, belting, or otherwise; and it is tobe further understood there may intervene between the engine shaft andthe rotor a clutch if desired. And it is to be further understood thatthe arrangements of Figs. 2, 3, 4, and 7 are not lmntive of myinvention, for it is obvious, in view of the disclosure of thesefigures, combinations of rotor and stator windings of difierent num bersand modes of connection may be em ployed.

What I claim is:

-1. The combination with an explosive engine, of means for starting thesame comprising a rotor and stator, a winding on the said rotorproducing a magnetic field of substantially constant direction withrespect to said rotor in all its positions, a stator winding, andswitching mechanism remote from said stator controllin said statorwinding, whereby the axis 0 the magnetic field produced by said statorwinding is progressively shifted with respect to said stator, said rotorand stator fields producing non-uniform torque having a maximumsubstantially simultaneously with maximum opposing engine torque.

The combination with an explosive engine, of means for starting the samecomprising a rotor and stator, a winding on said rotor producing amagnetic field of substantially constant direction with respect to saidrotor in all its positions, a stator winding, and switching mechanismhaving a member movable independently of sai rotor controlling saidstator windin whereby the axis of a magnetic field pr need by saidstator winding is progressively shifted with respect to said stator,said rotor and stator reacting on each other to produce non-uniformtorque having a maximum substantially simultaneously with maximumopposing engine torque.

The combination with an explosive engine, of means for starting the samecomprising a rotor and stator, a winding on said rotor producing amagnetic field of sub: stantially constant direction with respect tosaid rotor in all its positions, a stator winding, said rotor andstator-reacting on each other to produce non-uniform torque having amaximum substantially simultaneously with maximum 0 posing enginetorque, and switching mec anism having two movable members, one membermovable independently of said rotor, and one member moving insynchronism with said rotor, whereb the axis of the magnetic fieldproduced y said stator winding is progressively shifted with respect tosaid stator.

at. The combination with an explosive engine, of means for starting thesame comprising a rotor and stator, a winding on said rotor producing amagnetic field of substantially constant direction with respect to saidrotor in all its positions, a stator winding, switching mechanism havingtwo movable members, one member movable independently of said rotor, andone member moving in synchromsm with said rotor, whereby the axis of themagnetic field produced by said stator; winding is rogressively shiftedwith respect to said stator, and means for disen aging said movablemembers from each 0t er.

5. The combination with an explosive engine, of means for starting thesame comprising a rotor and stator, a winding on Said rotor producing amagnetic field of substantially constant direction with respect to saidrotor in all its positions, a stator winding, switching mechanism havingtwo movable members, one member movable independently of said rotor, andone member moving in synchronism with said rotor, whereby the axis ofthe magnetic field produced by said stator winding is progressivelyshifted with respect to said stator,

and means normally holding said movable dependently of said rotor, andone member moving in synchronism with said rotor, whereby the axis ofthe magnetic field produced by said stator winding is progressivelyshifted with respect to said stator, means normally holding said movablemembers disengaged from each other, and means for bringing said movablemembers into engagement' with each other.

7 The combination with an explosive en-' gine, of a starter thereforcomprising electro-dynamically reacting rotor and stator exerting onsaid engine a torque fluctuating in magnitude and attaining a maximumsubstantially simultaneously with a maximum opposing torque of saidengine, means for passing uncommutated current through said rotor, andmeans remote from said stator commutating the current in said stator.

8. The combination with an explosive engine, of a starter thereforcomprising electro-dynamically reacting members exerting on said enginea torque fluctuating in magnitude and attaining a maximum substantiallysimultaneously with a, maximum op posing torque of said engine, andswitching mechanism independent of said members controlling theirrelative movement.

9. The combination with an explosive engine, of a starter thereforcomprising electro-dynamically reacting members exerting on said enginea torque fluctuating in magnitude and, attaining a maximum substantiallysimultaneously with a maximum opposing torque of said engine, andswitching mechanism independent of said members controlling thedirection and rate of fluctuation of their'torque.

10. The combination with an explosive engine, of starting means thereforcompris ing a rotor and stator, rotor and stator windings, means formaintaining current flow through the rotor Winding in fixed relationthereto, and switching mechanism having a movable member independent ofsaid rotor for progressively changing the relations of the statorwindings, said rotor and stator reacting on each other to producenon-uniform torque having a maximum substantially simultaneously withmaximum opposing engine torque.

11. The combination with an explosive en- 4 gine, of means for startingthe same comprising a rotor and stator, rotor and stator windings, meansfor passing through the rotor winding a relativeiy large non-commu tatedcurrent, and i comm stat n controlling the stator winding comprising afixed member and a movable member movable independcntl y of said rotor,said rotor and stator reacting on each other to produce non-unr formtorque having a maximum substantially simultaneously with maximum opposmg engine torque.

12. The combination with an explosive engine, of means for starting thesame com-- prising a rotor and stator, a winding on said rotor producinga magnetic field of substantially constant direction with respect tosaid rotor in all its positions, a stator winding, switching mechanismhaving two incur bers movable into and out of engagement with eachother, one member movable independently of said rotor, and one membermoving in synchronism with said rotor, whereby the of the magnetic-fieldproduced by said stator winding is pmgressivcly shifted with respect tosaid stator, said rotor winding carrying a relatively largenoncommutated current and the current in said stator winding controlledby said switching mechanism being relatively small.

13. The combination with an xplosive engine, of means for starting thusame comprising a rotor and stator, a winding on said rotor, slip ringsmovabic with said rotor and connected to said winding, a stator winding,and switching mechanism therefor and remote therefrom comprising aplurality of non-rotating segments, ci'iopcrating rotating brushes, andslip rings in electrical communication with said brushes, said rotor andstator reacting on each other to produce nonuniform torque having amaximum substantially -llllllliilllttOUrillt' with maximum opposingengine torque.

14. The combination with an cxplr i gine, of means for sterling mic coneprising a rotor and s1 aior. a w in on said rotor, slip l'llilllOYtilI'lr with id 1 L connected tosaid winding", 1: H3101 winding,switching mechanism tln-rcfor and remote therefrom comprising aplurality of statimr ary segments, coopcrininp it'izl illg in and sliprings in electrii mmml ilh with said brushes, and liii'zllh isur'nlfliing said brushes and scfnnrm from each other.

i untherefrom comprising a plurality of stationary segments, cooperatingrotating brushes,

slip rings in electrical communication with said brushes, means normallyholding said brushes and segments separated from each other, and meansfor bringing said brushes and segments into engagement with each other.

16. The combination with an explosion engine exerting notruniformtorque, of means for driving the same in starting comprising a rotorconnected to the shaft of said engine and a stator, said rotor andstator producing magnetic fields re-acting on each other to produce anon-uniform torque attaining a maximum substantially simultaneously witha maximum opposing engine torque, sliprings and brushes for said rotorjuxtaposed thereto, and switching mechanism remote from said stator forprogressively shifting the magnetic field of said stator.

17. The combination with an explosion engine, of means for driving thesame com prising a rotor and a stator, a stator Winding, and switchingmechanism controlling said stator ing for progressively shifting thestat" @eld, said switching mecha nism comprising rotatable andnon-rotatable members normally disengaged from each other, and means forengaging said members with each other.

18. The combination with an explosion engine, of means for starting thesame comprising a rotor and'a stator, a stator Winding, switchingmechanism remote from said stator controlling said winding forprogressively shifting the stator field, said switching mechanismcomprising rotatable brushes, and cooperating non-rotatable segmentsconnected to said winding, and means for bringing said brushes intoengagement with said segments and for disengaging said brushes from saidsegments.

in testimony whereof I have hereunto affixed my signature in thepresence of the two subscribing Witnesses.

ROBERT C. HULL.

W itnes-ses:

MCKnn DUNCAN, EDWARD -LYNDON.

